Study, study, study and remember that equation because that's the most important thing about it. You should know how to graph the points out and pinpoint which number goes where. Other than that, watch Khan Academy videos! They're very helpful... or read an article.
An exponential function can describe growth or decay
It gets rapidly smaller as x increases, as illustrated by its graph. In the exponential growth of f(x), the function doubles every time you add one to its input x.
Since 40 acres of land produces 600 bushels so the bushels produced by 1 acres of land is 600/40=15 So bushels produced by 75 actes of land = 75×15=1125 bushels